I have no reason to doubt you, and I hope your rehab goes well. The privacy laws on healthcare are rigid as , and a doctor could seriously get his ass kicked for revealing any health-related information about a patient. I don't think his response means any more than Pop's quotes - unfortunately.
At Tim's age, something like an ACL would definitely be the end of his career. If they found something like that, I feel like they would have made an announcement by now. There wouldn't be anything to gain by prolonging it. I could see something like a small bit of floating cartilage, and they're waiting till the inflammation goes down, to see if he can finish the season without arthroscopic. It could also be just normal wear and tear inflammation, and Pop really does want to let him heal fully, so he hopefully won't be fighting it the rest of the way.
I don't know any more than anyone else. But if it was really bad news, I think we'd already know about it. At least that's what I'm going to tell myself.